Gear shaping machine with displaceable apron



.June 16, 1953 v E, w, MILLER 2,641,968

GEAR SHAPING MACHINE WITH DISPLACEABLE APRON Filed Sept. 16. 1948 10 Sheets-Sheet l www-Mn Y L, ne

June 16, 1953 E. w.

GEAR SHAPING MACHINE Filed Sept. 16. 1948 MILLER WITH DISPLACEABLE APRoN 10 Sheets-Sheet 2 M e m61@ June 16, 1953 E. w. MILLER 2,641,968

GEAR SHAPING MACHINE WITH DISPLACEABLE APRON Filed Sept. 16, 1948 10 Sheets-Sheet 3 June 16, 1953 E. w. MILLER 2,641,968

GEAR SHAPING-MACHINE WITH DISPLACEABLE APRON Filed Sept. 16. 1948 10 Sheets-Sheet 4 il? zz IM www@ June 16, 1953 E. w. MILLER 2,641,968

GEAR SHAPING MACHINE WITH DISPLACEABLE APRON Filed Sept. 16, 1948 10 Sheets-Sheet 5 @www E. W. MILLER GEAR SHAPING MACHINE WITH DISPLACEABLE APRON Filed Sept. 16. 1948 June 16, 1953 10 Sheets-Sheet 6 Illilllllllll l /7 Mray f f,

June 16, 1953 E. w. MILLER 2,641,968

GEAR SHAPING MACHINE WITH DISPLACEABLE APRON Filed Sept. 16, 1948 10 Sheets-Sheet '7 June 16, 1953 E. w. MILLER GEAR SHAPING MACHINE WITH DISPLACEABLE APRON l0 Sheets-Sheet 8 Filed sept. 1e. 194s June 16, 1953 E. w. MILLER 2,641,968

GEAR SHAPING MACHINE WITH DISPLACEABLE APRON Filed sept. 16. 1948 .$10 sheets-sheet e June 16, 1953 E. W. MILLER GEAR' SHAPING MACHINE WITH DISPLACEABLE APRON Filed Sept. 16,1948

-10 SheetsSheet 10 Patented June 16, 1953 GEAR. SHAPING MACHINE WITH nIsrLAoEABLgE Arnon Edward W. Miller, springfield, vt.,'assigmr to The Fellows Gear Shaper Company, Springfield, Vt., a corporation of Vermont Application september 16. 194,8, serio NQ. 49,531

This invention relates torv gear shaping machines of the well. known type which perform their cutting action by means of a cutter having teeth similar to those offa gear or pinion, but

Vprovided with cutting edges at one end, and

teethare generated in a gear blank by conjoint movements of relative axial -reciprocation be- 12 Claims. (Cl. 90-7') tween cutter and work piece and rotation about v their respective axes. It is more particularly related to machines of this type capable of producing finished gears, either external or internal, and having either straight spur or helical teeth, of a wide range ofhdiameters and face widths. Among the objectsof the invention are the renewing: I I'o provide feeding means such relative motions 'of approach between the cutter and work that the cutter teeth will penetrate into the work piece in a predetermined number of steps of predetermined length, with pauses between them while the cutting effect isv capable of causing Illustrative embodiments of means for accomplishing the foregoing objects are described in the following specification, and shown in the accompanying drawings, in connection with a gear lshaping machine of the type above designated;

and the invention comprises the means thus shown and all equivalents thereof.

In the drawings- Fig, 1 is a perspective view showing the front and right hand side of the illustrative machine;

Fig. 2 is a front elevation ofthe upper part of the right hand end of the machine shown in To provide, in connection with means foriimparting cutting and return movements to the cutter, new and improved adjusting means for shifting the limits of such movements without affecting their length;

To provide a new and improved back oi mtns for effecting separation betwen the work and cutter to prevent rubbing during the non cutting strokes of their relative reciprocation;

To provide a shiftable Work holder and means for shifting and supporting it so that it can be moved clear of overhead structure. to facilitate changing of large and heavy work pieces;

To provide in a machine of this typev speed changing mechanisms by which a variety of'different cutting speeds and diiferent rotary feeds may be imparted, independently of one another, to cutter and work and, in connection therewith, means convenient to the operator of the machine for shifting such transmission mechanisms To provide an improved means for imparting rotation to the spindle which carries` the cutter of such character that driving force is applied to the said spindle at the same side thereof as the engaging zone between the cutter and work piece, and obviate liability of `distortion of the shaft by which power is transmitted 'to such means. v

Fig.v l; p

Fig. 3 is a vertical section on planes parallel to the front of the machine and represented by thetline 3--3 of Figs. 5, 7 and 14;

Fig. i is a detail horizontal section on line 4*-4 of Fig. 3;

Fig. 5 is a horizontal section on line 5 5 of Fig. 3;

Fig. 6 is a detail vertical section taken on line S-- of Fig. 5 and shown on a larger scale;

Fig. '7 is a horizontal section taken on line 1--1 of Fig. 3 and Fig. '11;

Fig. 8 is a vertical cross section taken on line 8-8 of Fig. '7; .l

Fig, 9 is a front elevation of a set of change gears, partially shown in Fig. 7, by which rotation is transmitted to the work spindle;

Fig. 10 is a detail cross section on line lill0 ef Fig. 9;

Fig. 11 is avertical section taken on line I I-ll of Fig. 5 viewed fromthe rear;

Fig. 12 is a vertical section taken on line l2-l2 of Fie. 11:

Figi. 13 is a sectional view taken on line I3.-I3 of Fig. 14 and resolved into a vertical plane;

Fig. le is a vertical section taken on line I 4-l 4 of Figsj2 and 3;

vshown in Fig. 11;

Fig. 22 is a diagram of the mechanism, includingspeed changing transmissions, by which rotation is transmitted to the cutter and Work spindle;

Fig. 23 is .a diagram of the electrical system by which certain functions of the machine are i controlled. f

Like reference characters designate the vsame parts wherever'they occur in all the figures. A

The supporting structure includes a base and a superstructure 26 mounted thereon. A work spindle apron 21 is coupled with the base by means of a link 28 (Fig. '7) and pivots 26 and 30, and rests on supporting means later described. A work'spindle 3| is mounted rotatably in the apron 21 and is adapted to receive arbors, or other connecting means by which work pieces W of a wide variety of diameters and face widths may be secured vto rotate with the spindle. Such work pieces may be blanks for either external or internal gears in which straight or helical teeth may be generated.

The superstructure includes horizontal guideways 32 and 33 on which a cutter spindle carriage, or cutter saddle, 34 is supported and movable linearly. In the embodiment here shown, the work spindle is vertically disposed and the guideways are`horizontal.

In the carriage or saddle 34 a cutter spindle 35 (Fig. 3) is mounted with provision for rotation and axial reciprocation. Its axis is vertical and parallel with the work spindle axis. This spindle is adapted to carry a gear shaper cutter, of well known character, not here shown.

The means for reciprocating cutter spindle 35 consists of the following mechanism shown best in Figs. 3, l1, 13, 14 and 22. An electric motor 36, mounted in the interior of the base, drives, by means of sprockets 31 and 38 and a chain 39, a shaft 40. This shaft drives a parallel shaft 4I through a transmission gearing consisting of gears 42, 43, 44 and 45 xed on shaft and; sliding gears 46, 41, 48 and 49 splined. to the shaft 4|. A third shaft 50 is driven by shaft 4| through any one of three gears 5|, 52 and 53 (of which the gears 5| and 52 are connected together and splined on shaft 4|, and gear 53 is fixed to that shaft), which are adapted to mesh respectively with connected sliding gears 54 and 55 splined to shaft 50, and a gear 56 which has a rotative bearing on shaft 50. Gear carries an internal clutch 51 arranged to coact with an external clutch member secured to gear 56. Shaft 50 drives a crank shaft 58 by means of a pinion 56 and gear 60 fixed to these shafts respectively. A crank disk 6| is secured to the end of the crank shaft 58 adjacentvto the outer wall of the machine base.

By means of the sliding gear transmissions here described, any one of twelve differentspeeds may be imparted to the crank shaft. A crank pin 62 is mounted in a diametral guideway in the crank disk 6| and is adjustable radially by a screw 63. A pitman 64 having a screw threaded extension 64aV is coupled to the crank pin 62 and its screw threaded portion ismeshed with a gear element 65 keyed to a shaft 86 which extends between and in parallel with the guideways 32 and 33 and is supported at its ends in the superstructure. The pitman extension 64a is retained in mesh withl gear 65 by a tubular guide 61 to which bearings 68 are connected surrounding shaft 66 on both sides of gear 65.

Shaft 65 passes through the cutter carriage 34 and carries, in splined connection withl it, a gear element 68, shown dotted in -Fig. 3, which meshes with encircling rack teeth 10 on the cutter spindle 35. v Y l' 'The length of strokes of the cutter spindle may be altered by adjusting the crank pin 62 radially. The position of the spindle, and the Cri points at which its strokes begin and end, may be adjusted, without changing the length of the strokes, by rotating the pitman extension 64a. lThis extension is provided with a shank portion 84h, which occupies a tubular bearing in the main body of the pitman and is retained therein by lock nuts 64o. Its outer end projects to near the front of the machine and carries a square portion 64d which is accessible for engagement by a wrench for turning it. Due to its thread, which meshes with the gear 85, rotation of the extension 64d shifts the spindle upwardly or downwardly as may be desired. The convolutions of the thread act as rack teeth to rotate gear 65 and shaft 66 when the pitman is moved endwise. The part of the pitman which contains shank 64b is split at one side, as shown in Fig. 15, and is fitted with a screw 1| by which it may be tightcned on the shank to secure extension 64a in any rotated adjustment.

The cutter and work spindles are rotated simultaneously by the crank shaft 58 through a worm 12 on the crank shaft at the opposite end thereof from the crank disk 6|. Worm 12 meshesv with a Worm wheel 13 on a shaft 14 (Figs/1l, 12 and 13). This shaft carries one memberV 15 of a pair of changeable gears, the other member, 16, of which is mounted on an intermediate shaft 11, from which rotation is transmitted to a third shaft 18 through connected pairs of sliding gears 19 and 80 on shaft 11 and a cluster gear 8| on shaft 18. A bevel gear 32 on'shaft 18 is adapted to be lmeshed with either of two connected bevel gears 83 and 84, which are located at diametrically opposite sides .of the gear 62 and are splined to an upright'shaft 85. Gears 83 and 84 are coupled with a shifter 86 in the form of a sleeve which surrounds shaft 85 and is adapted to be moved endwise by means of a pinion 81 meshing with rack teeth on the exterior of the sleeve and rotatable by a hand crank 38'on the shaft of the pinion, whereby either gear 83 or 84 may be put in mesh with gear 32.

By appropriately selectedmesh of the sliding gears 19 and 80 with elements of the cluster gear 8|, and appropriate setting of gearsv 83 and 84, any one of four different rotative speeds can be imparted to the shaft 85 in either direction.

The work spindle is rotated by shaft 85 through a bevel gear B9 on its lower end (Figs. 3 and 1l), which meshes with a bevel gear 60 on a shaft 6| (Fig. '7), which, through a set of changeable gears 82, 93, 94, 95, and 96 (see also Figs. 9 and l0), drives a shaft 81 carrying a worm 98 meshing with a worm wheel 69 secured to the work spindle 3| at the under side of the apron 21.

Shaft 85 transmits rotation to the cutter spindle from a bevel gear |0|'on its upper end through either of two bevel gears |02 and |03 at opposite sides of its axis, which are splined to a shaft |04 (parallel to the cutter saddle guides) and are adapted to be shifted so as to bring either one into mesh with gear |0|. A housing |05 (Fig. 5) is mounted in the cutter saddle 34 and is formed with a portion which surrounds the shaft |04. This housing contains a bevel gear |06 splined to shaft |04 and meshing with a bevel gear |01 Which is secured to a shaft |08, rotatably mounted in the main partv of the housing. A worm |09 is mounted on the shaft |08 and meshes with a worm wheel ||0- direction as the work spindle or in the opposite direction.

An important feature of the gearing between the shaft |04 and worm wheel H0 is that the housing |05 extends forwardly from the shaft |04 and is slidable with the cutter'saddle 34 lengthwise of that shaft, and it is adjustable in the saddle so that the worm |09k can be brought into close and accurate mesh withthe worm wheel and adjusted to compensatel for wear, without causing any distortion ofthe shaft |04. 'Shms H35! (Fig. 5) of different A thicknesses may be placed between the inner wall of the housing and the structural web of the saddle 34 to which this housing is secured, in order to obtain exactly correct mesh between the worm and the wheel.

Another advantageous feature of this construction is that the worm |05 is Iat the same side of the worm wheel ||0 as the zone of engagement between the cutter and a work piece on the work spindle. This gives an improved control of the cutter spindle.

The mounting of the work spindle apron by means of link 28' and pivots 29 and-30, as described, enables the apron to be withdrawn from its Working position in the machine base and swung forwardly clear of the superstructure to permit changing of ylarge and heavy work pieces. The end of the apron remote from that which is engaged with pivot 30 is contained in a recess in the base and held in closeengagement with bearing points in the base,v two of which are shown at ||4 and vH5' in Fig. 3 at the left of spindle 3|.

For moving .the apron into and out^of en-l gagement with its bearing points in the base, a toggle mechanism is provided, which is shown in Fig. ll, and parts of which appearalso in a Figs. l and 7. A link H6 (which is adjustable in length) is coupled by means of ball and socket joints with a rearwardly extending arm Il? of the link 2S and with one arm of a bell crank lever H3, which is pivoted at l |9 to they base structure. A toggle linkage is pivoted at on the base and consists of links |2| and |22, connected together byaknuckle pivotl |23.

Link |22 is coupled at `A|24 with the second' bearing points H4, H5, until a bearing surface |29 on the lower end of the worm wheel39 (Fig. 3) rides over and rests, upon a roller |35 carried by a supporting piece i3| which is connected by a pivot |32 with the bass structure rand carries a roller v|33 in theunderpartcf its A'flange 21| of the apron overlaps Ythe adjacent part of thebase which thus supports that part; of' the apronf free end which rests on an arcuate flat' track Pivot- |34 on the base (shown also in Fig. l). is then brought into alignment with pivot |32. The track |34 is concentric with pivot |32 and extends far enough to permit outward swinging movement ofthe apron, and a work piece` connected with the work spindle,y clear of the structure above. Y

.A novel back off mechanism is provided for slightly retracting the apron .from its bearing points ||4, l5 when'the cutter spindle makes '1 its noncutting return strokes, and bringing it sitions while the cutter reciprocates.

rmly against the bearing points when the working strokes take place. This mechanism is shown in Figs. '7, 8 and 1'1. It comprises a back oli' cam |35 secured to .a shaft |36, which is driven from the crankshaft 58 by a pair ofk bevel gears |31, a shaft |38 and a coupling |39 between the shafts |36 and 438.V It furthercomprises a lever |40 connected byra pivot |4| with the base structure and having an arm projecting toward the apron 21 carrying a gear segment |42 on its extremity. The teeth of this gear segment mesh with the teeth on the adjacent end of a block |43 which is mounted nonrotatably. in the apron and is movable endwise toward and Y away from the gear segment |42.

The longer arm of lever |40, which projects rearward from its pivot |4|, carries an extension |44 on which are mounted'rolls |45 and |46 ankingvthe back oli' cam |35.

Back on cam |35 is rotated in one to one ratio with the crank shaft and has a low dwell and a high dwell, each extending around nearly 130 ofA its circumference, suitably disposed to shift and hold the apron in the prescribed po- The extension |44 is connected to the lever |40 by a n pivot |47 and clamp screw |43 and is adjustable angularly about the pivot |47, as may be needed to ensure a rm contact 'of the apron with rbearing points 4, 5, by screws |49 mounted projects through a cover on the front of the base (Fig. 1) where it is accessible for manipulation by the operator. When in the position shown in the drawings, vit holds the block |43 in mesh with the back olf lever, but it may be turned until a low part |52 (Fig. 8) of the cam is brought adjacent to the outer end of the block, when a spring pressedpin |53, bearing against a flange |54 on the block, moves the latter outwardly far enough to bring its teeth out of mesh with the teeth of the back orf lever.

The cutter saddleA 34 'can be moved along the guides 32 and 33 to accommodate the cutter to external yor internal gear blanks of any diameter within the working range of the machine, and it is automatically so moved for feeding the cutter to depth in a predetermined number of steps, and for withdrawing the cutter when the A depth feed cam |55 and a lead screw |56 serve these purposes. The depth feed cam has a circumference of gradually increasing radius and a sharp drop at |5Ibetween its highest and lowest points. It

G acts through a bell crank lever |58 having a roll |59 on one arm, which bears on the circumference of the cam, and a gear segment |60 on the other arm which engages the teeth of a rack |6| secured to one end of the lead screw |56. The lead screw is supported nonrotatably at its opposite ends in parallelism with the guides 32 and 33, and passes through a nut |62 (Fig. 4) carried by the cutter saddle 34, and with which the threads of the screw mesh. The nut can be rotated to propel the saddle in either direction, for setting it to correspond with different Work pieces, by means of a shaft |63 carrying a pinion |64 in mesh with face gear teeth |65 on the end of the nut, and the outer end of which is accessible at the front of the machine for application of a wrench for rotating it.

The depth feedcam is rotated by mechanism, of which a part is shown in Fig. 3 and the major portion in Figs. 14, 17 and 18. Referring to Fig. i

anchored on the base, is connected with the bell A crank lever |68 in a manner to tend to hold roll |61 against cam |66 and Withdraw rod |1| to the right from the position shown in the drawing.

Pawl |12 coacts with a ratchet wheel |16 to turn the ratchet when the pawl rod |1| is moved from right to left by the cam |66. An adjustable stop screw |11 is mounted in a Xed bracket |18 in position to engage arm |13 and limit the spring-retracted movement of the pawl to any amount between one tooth pitch of the ratchet wheel |16 and the full throw of the cam.

A lock lever |19 is pivoted at |80 (Fig. 20) to a part of the bracket |18 and is pressed upon by a spring |8| toward the bar |1| in a position such that a toe in its extremity will enter a notch |82 in the bar when the latter has been advanced by the full throw of cam |66. Fig. 14 shows the bar thus locked so that it cannot be retracted by spring and hence is not capable of being moved by cam |66. A solenoid |83 is arranged so as, when energized, to withdraw the lock lever |19 and permit actuation of the pawl by the cam.

Ratchet |16 is mounted on a shaft |84 (Fig. which carries a worm |85 meshing with a gear |86 rotatable about the shaft |81 on which the depth feed cam is secured. Gear |86 carries a pawl |88 engaging a ratchet |89 keyed to shaft |81. This ratchet and pawl combination constitutes a one way clutch which transmits rotation from gear |86 to shaft |81 but permits the shaft and depth feed cam to be rotated ahead of the automatic drive by an externally accessible shaft |90 carrying a pinion |9| which meshes with a gear |92 xed on shaft |81.

It will be apparent from the foregoing that the depth feed cam is rotated through a short step, which may be varied in length, with each rotation of the crank shaft, whenever the pawl and ratchet couple |12-|16 is not put out of action by the lock or detent |19.

A constant force is applied to the lead screw |56 and through the rack |64 to hold the roll |59 against the depth feed cam, and cause this roll to enter the depression |51 of the cam, by

means of a spring |93 (Fig. 14). This spring reacts against the stationary base structure of the machine land is connected with a chain V|94 which passes around a sprocket |95 on a shaft |96 (Fig. 1'1), to which a pinion |91 is secured. This pinion meshes with the rack |6|.

An important feature of the machine is automatic means by which the depth feed cam is operated to cause feeding of the cutter to full depth in the work piece in a series of steps, with pauses between successive steps while the work piece is rotated through a complete revolution or other predetermined angle. For this purpose a timer |98 (shown dotted in Fig. 11, and further shown in-Fig. 21). is mounted in the base structure and a disk |99 (Figs. 14 and 19) is secured to the shaft |81. The timer has a rotatable member 200 (Fig. 21) for controlling contactors vin the electrical system, which is rotated by a face gear 20| and pinion 202. This pinion is driven in time with the work spindle by'a exible shaft 203 which is connected with the shaft of the spindle-driving worm 98 (Fig. 7).

Disk |99 carries on its outer face a number of circumferentially adjustable dogs 204 which are secured by bolts of which the heads lie in an undercut circular groove 205, in the outer face of the disk |99. Two such dogs (Fig. 19) or a much larger number of them (Fig. 2) may be mounted on the disk and adjusted at varying angular degrees apart around the axis of the disk. There is a degree scale 206 on the face of the disk by which the angular settings of the dogs may be determined.

These dogs act, in the course of rotation of the depth feed cam |55 and disk |99, to raise a lever 201 and thereby shift a switch 208 in the electrical system. Each dog has a sharp rise at one end and the lever has a sharp protuberance on its under side in the path of the dogs, whereby the displacement of the lever caused by the dogs is of limited duration and the release of the lever occurs suddenly. y The dog controlled switch 208 and the timer are correlated in the electrical system to the following effect. The timer is geared to make an electrical contact after the work spindle gear 99 has made a 'complete rotation. This contact energizes the solenoid |83 and disengages the detent |19 from the pawl carrying bar |1|', thereby enabling the ratchet Wheel |16 to be rotated and to apply rotation to the depth feed cam and disk |99. When a dog 204 raises the switch 208 actuating lever 201, the switch controlled thereby causes the solenoid to be deenergized and the timer to be energized, whereby the detent |19 is caused to prevent further driving of the depth feed cam.

Disk |99 carries a nonadjustable dog 2|0 on its inner face which is angularly related to the depression 51 of the depth feed cam to displace a lever 2|| (similar to lever 201) when the cam depression arrives at the position shown in Fig. 3 and thereby shifts a switch 2|2 in the electrical system which causes the machine to s op.

The sliding gears 46-49, 5|, 52, 54, 55 in the driving train by which the cutter spindle is reciprocated are controlled and operated by manual means at the right hand end of the machine through mechanisms as follows. Referring to Figs. 5 and 11, a shifter bar 2|5 is connected at one end with a yoke 2|6 which engages the shiftable gear unit 48-49, and its other end carries a studl which enters a groove 2|1 in a by a yoke 22 I 'with the gear unit l5-41 and lwith .a second groove v222 in the cam 2 I8.

Similar gear shifter bars 223 and 224 are coupled with the sliding gear units l-52 and 5ft-55,

respectively, and with separate encircling grooves 4in a cylindrical cam 225 which is rotatable on a pivot shaft 226. The cam grooves are formed with offsets, as shown in Fig. l1 with respect to the groove 222, and the cams are yieldingly held in their various positions by spring pressed balls 221 and 228 (Fig. 14), which enter notches in the circumferences of the cams. 'A l' The manual means for rotating the cams isa crank 229, shown in Figs. 1, 2, 5 and 14. Itis connected witha Worm230 (Fig. 6) vmeshing with a worm wheel'23I which is rotatable about a shaft 232, being supported bya sleeve 233 which surrounds shaftV 232 and isv movable endwise thereon as well as being rotatable about the shaft. Cylindrical dials 234 and 235 are mounted rotatably at opposite sides of the worm gear 23| Y and are adapted to be coupled interchangeably lto the latter by means of clutch elements 235 and 231 on the sleeve 233 which are in sliding clutched engagement with the worm gear. The clutch elements can be placed also in a neutral position, which is that shown inFig. 6.

The clutch sleeve is placed in its various positions by means of a piniony 238 which meshes With encircling rack teethv 239 and is connected with a knob 240 at the front of the machine structure.

The dial 234 carries a sprocket element 2d! which is connected by a chain 242 (Fig. 2) with one element of a double sprocket 253, the other element of which is connected by a chain 2414 (Fig. 5) With a sprocket connected to the cam 225. Dial 235 carries a sprocket element 245 connected by a chain 246 with one element of a double sprocket 241, the other element of which is connected by a chain 245 with a sprocket 249 which is secured to cam 2 I8.

Thus, by rotation of crank 229, with selective coupling of either dial 234 or 235 with the worm Wheel 23|, either cam 2I8 or 225`can be rotated andthe various sliding gears selectively shifted to obtain any one of the total available number of reciprocation speeds of the cutter spindle. The dials 234 and 235 carry indicia (shown in Fig. 2 as letters) on their circumferences, which are visible' through windows in the cover wall of the'machine structure and serve to identify the positions of the sliding gears.

Shaft 232 can be vrotated independently of the dials by means of a crank 259 so as to reciprocate the cutter spindle manually. For this purpose a'sprocket 2.5i is keyed to the shaft and is coupled by a chain 252 with one element of adouble sprocket 253, the otherl element of which is coupled by a chain 254 with a sprocket'255 on a shaft 256. A sliding gear 251 splined on this Ashaft is adapted to be brought into mesh with a gear 258 (Fig. 13) on the transmission shaft 4I of the spindle-reciprocating mechanism. Gear 251 is normally held out of mesh by a spring 259 and is brought into mesh at need by a shifter 260 operable by a lever 26I through connections not shown in these drawings.

The sliding gears 19 and 80 of therotary feed transmission (shown in Fig. 12), are shiftable into various positions of mesh with the cluster gear BI by `a lever 262 at the left front of the machine structure which is movable through H vslots into any of four different positions and Y operates gear Shifters, one of which is shownvat 263 in Fig. 11, through means shown by dotted lines. As such means are of conventional character, involvingnothing Anovel in the present invention, it is considered unnecessary to show or describe them in detail.

It is to be understood that the invention which I claim is not limited to the specific details of means and mechanisms described in the foregoing specification, but that it embraces all equivalent means capable of accomplishing like and comparable resultsk to those accomplished yby the means herein described.

What I claim is:

1. In a gear shaping machine having a shiftable spindle carriage, a spindle mounted in said carriage tov reciprocate endwise, a crank shaft, and means operated by said crank shaft for reciprocating said spindle, a cam rotatable in unison with said shaft, a depth feed cam disposed for applying force to said carriage so as to shift it linearly, mechanism operated by said first named cam for imparting step by step movement to the depth feed cam, an electrically controlled lock normally engaged with said mechanism 'to prevent transmission of rotation to the depth feed cam, a rotatable work spindle, a timer having a rotatable element driven in unison with said work spindle, means whereby said timer causesl said lock to be released, whereby actuationof the depth feed cam is caused to take place, a dial rotatable simultaneously with the depthfeed camV and means operated by said dial for activating deactivating the timer.

2. A gear` shaping machine comprising a supporting structure, rotatable Work and cutter spindles, a carriage mounted on the supporting structure in which one of said spindles is contained with provision for axial reciprocation, a depth feed cam, transmission means between said cani and spindle carriage by which the cam in its rotation causes the carriage to be displaced, means for reciprocating the spindle in said carriage including a rotatable crank, a cam connected with said crank for rotation simultaneously therewith, a pawl device operable by the last named cam for back and forth reciprocation, a ratchet arranged to be rotated step by step by said pawl and geared to the depth feed cam so as to transmit rotation thereto, a lock organized to engage said pawl device so as to prevent movement thereof, a solenoid associated with said lock so as, when energized, to vrelease the lock, means for rotating the cutter and work spindles simultaneously in a prescribed speed ratio, a timer including a movable element geared to the spindle rotating means for movement in timed relation therewith and having means for energizing the solenoid. so as to release the lock, a dialassociated for rotation in timed relation withtheV depth feed cam and electricalr lconnections operated by said-dial for deenergizing the V.solenoid and' energizing the timer.

3. In a gear shaping machine, a cutter spindle, a work spindle, an apron in which one of said spindles is rotatably mounted, a holder in which ythe other spindle is rotatably and reciprocably mounted, means for rotating said spindles in a prescribed ratio, means for reciprocating the cutter spindle including a crank shaft, a back off lever for the apron having geared connection with the apron, and a back oif cam in driven connection with said crank shaft organized to impart oscillating movement to said lever.

4. A gear shaping machine according to claim 3, in which the back off lever is provided with a gear segment adjacent to the apron and the apron is provided with a shiftable block having teeth in mesh with said gear segment, said block being retractable from the back off lever to disengage its teeth from the teeth of the gear segment, whereby to permit displacement of the apron from its operative position in the machine.

5. In a gear shaping machine, a supporting structure, a work spindle apron mounted on said structure, a work spindle rotatably held by said apron, mechanism normally holding the apron in working position with respect to the base but operable to shift the'apr-on away from the base, a back off mechanism for the apron including a mechanically oscillated lever having a gear segment and a toothed block mounted on the apron in mesh with said segment, said block being disengageable from the gear segment to permit retraction of the apron.

5. In a gear shaping machine, a supporting structure, a work spindle apron mounted thereand movable linearly and angularly from its operating position, and a pivotally mounted supporter for said apron arranged `to receive the apron when retracted linearly from its operating position and being rotatable about its pivot when the apron is supported upon it so as to enable the apron to be swung in a manner to carry the work spindle away from the supporting structure.

7. In a gear shaping machine including a supporting structure, a spindle carriage movable on said structure in a straight path, and a spindle rotatably mounted in said carriage, means for rotating the spindle including a shaft parallel with the carriage path, a housing movable lengthwise of said shaft and connected with said carriage, a shaft contained in said housing extending away from the first named shaft, intermeshing gears contained in said housing and mounted on the respective shafts, and intermeshing gear elements on the second shaft and the spindle, respectively, arranged to transmit rotation to the spindle.

8. A gear shaping machine including a supporting structure, cutter and work spindles mounted on said structure for rotation about their respective axes, one of said spindles being reciprocable endwise, and mechanism for reciprocating the last named spindle comprising a shaft, a plurality of gears secured to said shaft with spaces between them, a second shaft parallel to the before named shaft, sliding gears splined to the second shaft displaceable into mesh exclusively with different ones of the gears on the first named shaft, a crank driven by the second shaft, and connections between said crank and the endwise movable spindle for imparting endwise reciprocation to the spindle.

9. A gear shaping machine according to claim 8 combined with means for shifting the shiftable gears, which comprises a cam, and a gear shifter coupled with said sliding gear and engaged with the cam.

10. A gear shaping machine according to claim 8 combined with means for shifting the slidable gears on the second named shaft, Which'includes a cam, a gear shifter coupled with said sliding gear and engaged with the cam in a manner such that rotation of the cam moves the sliding gears axially, a rotatable sprocket adapted to be rotated by the machine operator, and a transmission chain between said sprocket and cam.

11. In a gear shaping machine, a shiftable spindle carriage, a spindle mounted in said carriage to reciprocate endwise, means to reciprocate said spindle in said carriage, a cam moveable in unison with said reciprocating means, a depth feed cam connected to said carriage so as to shift it linearly, mechanism operated by said firstnamed cam for imparting step by step movement to the depth feed cam, a lock normally engaged with said mechanism to prevent rotation of said depth feed cam, a second spindle, means to rotate said second spindle, a timer having an element dri-ven in unison with said second spindle and means whereby said timer causes said lock to be released whereby actuation of the depth feed cam is caused to take place.

12. In a gear shaping machine having a shiftable spindle carriage, a spindle mounted -in said carriage to reciprocate endwise, means to reciprocate said spindle in said carriage, a cam moveable in unison with said reciprocating means, a depth feed cam connected to said carriage so as to shift it linearly, mechanism operated by said rst-named cam for imparting step by step movement to the depth feed cam, a lock normally engaged with said mechanism to prevent rotation of said depth feed cam, a second spindle, means to rotate said second spindle, a timer having an element driven in unison with said second spindle, means whereby said timer causes said lock to be released whereby actuation of the depth feed cam is caused to take place, a dial moveable simultaneously with said depth feed cam, and means operated by said dial to activate and deactivate said timer.

EDWARD W. MILLER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,231,255 Hanson June 26,1917 1,490,894 Einstein Apr. 15, 1924 1,961,396 Schmitt et al June 5, 1934 2,068,889 Roehm et al Jan. 26, 1937 2,103,911 Miller Dec. 28, 1937 2,125,304 Miller Aug. 2, 1938 2,126,339 Miller Aug. 9, 1938 2,306,910 Sykes Dec. 29, 1942 2,435,405 Praeg Feb. 3, 1948 

